module.exports = class Mcaptcha {
    constructor(options) {
        this.options = options;
        this.fontSize = options.height * 3 / 6;
        this.init();
        this.refresh();
    }
    init() {
        this.ctx = wx.createCanvasContext(this.options.el);
        this.ctx.setTextBaseline("middle");
        this.ctx.setFillStyle(this.randomColor(180, 240));
    }
    refresh() {
        var code = '';
        var txtArr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
        for (var i = 0; i < 4; i++) {
            code += txtArr[this.randomNum(0, txtArr.length)];
        }
        this.options.createCodeImg = code;
        let arr = (code + '').split('');
        if (arr.length === 0) {
            arr = ['e', 'r', 'r', 'o', 'r'];
        };
        let offsetLeft = this.options.width * 0.6 / (arr.length - 1);
        let marginLeft = this.options.width * 0.2;
        arr.forEach((item, index) => {
            this.ctx.setFillStyle(this.randomColor(0, 180));
            let size = this.randomNum(24, this.fontSize);
            this.ctx.setFontSize(size);
            let dis = offsetLeft * index + marginLeft - size * 0.3;
            let deg = this.randomNum(-30, 30);
            this.ctx.translate(dis, this.options.height * 0.5);
            this.ctx.rotate(deg * Math.PI / 180);
            this.ctx.fillText(item, 0, 0);
            this.ctx.rotate(-deg * Math.PI / 180);
            this.ctx.translate(-dis, -this.options.height * 0.5);
        })
        for (var i = 0; i < 4; i++) {
            this.ctx.strokeStyle = this.randomColor(40, 180);
            this.ctx.beginPath();
            this.ctx.moveTo(this.randomNum(0, this.options.width), this.randomNum(0, this.options.height));
            this.ctx.lineTo(this.randomNum(0, this.options.width), this.randomNum(0, this.options.height));
            this.ctx.stroke();
        }
        for (var i = 0; i < this.options.width / 4; i++) {
            this.ctx.fillStyle = this.randomColor(0, 255);
            this.ctx.beginPath();
            this.ctx.arc(this.randomNum(0, this.options.width), this.randomNum(0, this.options.height), 1, 0, 2 * Math.PI);
            this.ctx.fill();
        }
        this.ctx.draw();
    }
    validate(code) {
        var code = code;
        var v_code = this.options.createCodeImg;
        console.log("输入的验证码"+code)
        console.log("生成的验证码"+v_code)
        console.log(v_code.substring(v_code.length - 4))
        if (code == v_code.substring(v_code.length - 4)) {
            return true;
        } else {
            return false;
        }
    }
    randomNum(min, max) {
        return Math.floor(Math.random() * (max - min) + min);
    }
    randomColor(min, max) {
        let r = this.randomNum(min, max);
        let g = this.randomNum(min, max);
        let b = this.randomNum(min, max);
        return "rgb(" + r + "," + g + "," + b + ")";
    }
}